Pump



Feb. 21, 1967 w. E. COPELAND 3,304,875

PUMP

Filed Feb. 23. 1965 5 Sheets-Sheet 1 Fig.2

Feb. 21, 1967 w. E. COPELAND 3,304,875

PUMP

'1 d F b. F1 e e 23 1964 3 Sheets-Sheet B Feb. 21, 1967 Filed Feb. 25. 1965 W. E. COPELAND UMP 5 Sheetsheet 5 ,iiii in- United States Patent 3,304,875 PUMP Wayne E. Copeland, Los Angeles, Calif., assignor to Aetna Chemical Corporation, Burbank, Calif., a corporation of California Filed Feb. 23, 1965, Ser. No. 434,450 4 Claims. (Cl. 10387) The present invention relates to electric motor-driven centrifugal pumps for use with highly corrosive fluids, and it relates more particularly to an improved electric motorpump combination of the above-mentioned type.

The pump to be described is of a molded plastic construction; the pump housing and impeller being formed,

for example, of a polycarbonate plastic material. The

polycarbonate plastic marketed by the General Electric Company under the trade name Lexan is suitable for the purpose. Polycarbonate plastics are advantageous because they are easy to mold; and they are not susceptible to corrosive attack by acids, or the like. Moreover, polycarbonate plastics are capable of operating at high temperatures of the order, for example, of 250 F.

The pump housing in the embodiment of the invention to be described is made in two parts. These two parts are held together by a multiplicity of bolts, composed, f-or example, of stainless steel. In a constructed embodiment of the invention, twenty-three such bolts were used to assure that there would be no leakage, and to prevent distortion of the plastic material at the higher operating temperatures.

As will be described, the pump itself is a centrifugal type, and it is mounted on the drive motor in an improved and simplified manner. The pump shaft is formed, for example, of titanium, and it is inserted into a counterbore in the motor shaft in axial alignment with the motor shaft. The pump shaft is coupled to the motor shaft, for example, by appropriate pins.

The pump shaft extends into the pump housing and into the impeller of the pump. The end of the pump shaft is formed, for example, into a hexagon so as to mate with a hexagon aperture at the'center of the impeller. This particular coupling, instead of the usual threaded coupling of the prior art pumps, permits the pump accidentally to be driven in reverse without adversely affecting the mechanism due to any decoupling tendencies.

"A seal assembly is mounted in the pump housing in the embodiment to be described, and the seal assembly includes a stationary seal mounted on the pump housing and a rotating seal which rotates with the pump shaft and which engages the stationary seal in a sealing relationship. The rotating seal in the embodiment to be described is spring loaded to perform its scaling function, and it is coupled to the impeller by means of axial pins so that it may rotate with the shaft. This particular coupling of the rotating seal provides an inexpensive and practical assembly, without any need to clamp the rotating seal to the pump shaft by set screws, or the like, which is usually impractical due to the nature of the material of the pump shaft.

The features of the invention which are believed to be new are set forth with particularity in the claims. The objects and advantages of the invention, however, will become apparent from a consideration of the following description, when the description is taken in conjunction with the drawings, in which:

FIGURE 1 is a perspective view of an improved pumpmotor combination constructed in accordance with the concepts of the invention;

FIGURE 2 is a side view of the pump-motor combination of FIGURE 1, and particularly illustrating the manner in which the pump is mounted on the motor;

FIGURE 3 is a fragmentary view, partly in section, and particularly illustrating the manner in which the pump shaft is coupled to the motor drive shaft, and also the manner in which the pump shaft is coupled to the im-- peller of the pump;

FIGURE 4 is a sectional view of the pump, taken substantially on the line 44 of FIGURE 2;

FIGURE 5 is a rear view of the pump, taken along the line 55 of FIGURE 4, and on a reduced scale with respect to FIGURE 4;

FIGURE 6 is a view of the pump impeller, taken substantially on the line 66' of FIGURE 4, and on a reduced scale with respect to FIGURE 4; and

FIGURE 7 is an exploded view of the pump illustrating its various components.

The pump-motor combination of the present invention, as shown, for example, in FIGURE 1, includes an electric motor 10 which is mounted on an appropriate pedestal 12. The combination also includes a centrifugal pump 14 which is mounted on the motor 10 in a manner to be described.

The pump 14 includes a pump housing which, in turn, comprises a front section 16 and a rear section 18. These sections cooperate to form a pump housing having an essentially cylindrical configuration, as shown.

The pump housing may be formed, for example, of a polycarbonate plastic. For example, as mentioned above,

the polycarbonate plastic marketed by the General Electric Company under the trade name Lexan has proven to be satisfactory. The two pump housing sections 16 and 13 are held together by a plurality of bolts and screws designated 20. These bolts and screws extend axially through the sections adjacent the periphery thereof, and may be formed "of stainless steel. In a constructed embodiment of the invention, for example, twenty-three such bolts were used to hold the two sections 16 and 18 together.

As best shown in FIGURE 7, the pump housing section 16 has an annular taper 22 formed in its inner face, and this taper extends around the section 16 adjacent its periphery. The pump section 18, on the other hand, has

an annular groove or channel 24 extending around its inner face adjacent the taper 22.

An O-ring 26 (FIGURE 4) is mounted in the groove 24, and this O-ring is distorted by the taper 22 into sealing relationship when the two housing sections 16 and 18 are bolted together by the bolts 20. The resulting assembly forms an effectively sealed housing for the corrosive fluid which is pumped by the pump.

The section 16 has an inlet port 28 formed in its central portion, and this inlet port receives a suitable pipeline, or the like, which feeds the corrosive fluid to the pump. The section 18, on the other hand, hasan outlet port 30 through which the corrosive fluid under pressure is discharged. This latter port may be coupled, likewise, to an appropriate pipeline.

As shown in FIGURE 2, the pump housing section 18 has a plurality of protuber'ances 32 formed on its rear face. These protuberances support a metal mounting ring 34. The mounting ring 34 is attached to the ends of the protuberances by counter sunk screws 35, for example, which are threaded into the protuberances. The mounting ring 34, in turn, is mounted to the casing of the motor 10 by means, for example, of appropriate bolts 36 which are threaded into the casing.

As best shown in FIGURE 3, the motor 10 includes a drive shaft 40 supported, for example, in a bearing 42. The drive shaft 40 is counterbored to receive a pump shaft 44. The pump shaft 44 extends into the drive shaft 40 in axial alignment therewith. The pump shaft 44 is composed, for example, of titanium, or other material which is not susceptible to corrosive attack by the fluids handled by the pump. The pump shaft is affixed to the drive shaft 40 by means, for example, of a pair of mutually perpendicular pins 46 and 48 which extend through the two shafts.

A pump impeller 50 is mounted to the end of the pump shaft 44 remote from the drive shaft 40. The impeller is disposed within the pump 14. The remote end of the pump shaft 44 is formed into a hexagon, for example, so as to mate with a hexagon aperture at the center of the impeller 50. The impeller is held on the pump shaft 40 by means, for example, of a titanium screw 52 and a titanium washer 54. The particular illustrated coupling of the pump shaft 44 to the impeller 50 permits the motor accidentally to be driven in reverse, Without any tendency for the pump shaft to be decoupled from the impeller, with resulting damage to the assembly.

The impeller 50, like the pump housing 14, may be formed of a polycarbonate plastic, such as Lexan. The impeller, as best shown in FIGURES 4 and 6, is provided with appropriate vanes 52 so that, when the impeller is rotated, it causes the corrosive fluid to be drawn in through the inlet port 28, and by centrifugal action, causes the fluid to be discharged under pressure from the outlet port 30. A plurality of radial vanes 54 are formed on the rear face of the impeller 50. These latter vanes function to drive the corrosive fluid away from the central portion of the impeller, where a seal combination is provided between the shaft and the pump housing 16, as will be described.

The aforesaid seal combination is designated generally as 80. The combination includes a rotating seal which is rotatably supported on the pump shaft 44 in the pump housing 14. Since the titanium shaft is not susceptible to receiving set screws, or the like, the rotating seal may be conveniently coupled to the impeller 50 by a pair of axially extending pins 82. This permits the rotating seal to rotate with the impeller 50 and with the pump shaft 44.

The rotating seal includes 'a housing 84 which may be formed, for example, of titanium or a polycarbonate plastic. A plurality of springs, such as the spring 86, are encased within the housing 84. These springs may be formed, for example, of a metal marketed by the Elgin Watch Company and designated by the trade name Elgiloy. This metal exhibits resilient characteristics, and is not suspectible to corrosive attack by the fluids handled by the pump.

An annular member 88 is also supported within the housing 84, and this annular member may also be composed of Elgiloy. The annular member 88 bears against a further annular member 90 which has a wedge shaped configuration, and which may be composed of Teflon. The member 88 is retained in the housing by means, for example, of a snap ring 92. The wedge shaped annular member 90 bears against a bearing member 94 which may be composed of carbon.

A further bearing member (which may also be cornposed of carbon) is supported in a stationary manner in the section 18, this latter member being designated 96. The stationary bearing member is supported in a groove in the section 18 by means, for example, of a rubber boot 88. The rotating bearing member 94 is biased against the bearing member 96 and rotates about the latter bearing member as the rotating bearing assembly 80 is rotated.

The above described seal combination 80 provides an adequate and efficient seal for the pump assembly, and one which is not susceptible to attack by the corrosive fluid.

The invention provides, therefore, an improved pumpdrive motor combination for handling corrosive fluids. The pump of the present invention can be constructed on a relatively economical basis, and can be sold for a relatively low price. The pump has been found to perform with a high degree of satisfaction, and to operate satisfactorily in handling highly corrosive fluids.

While a particular embodiment of the invention has been shown and described, modifications may be made. It is intended in the claims to cover all such modifications which fall within the scope of the invention.

What is claimed is:

1. A pump and drive motor combination for corrosive liquids including: a drive motor comprising a drive shaft and a casing; a pump shaft coupled to said drive shaft; a pump impeller mounted on said pump shaft; a pump housing enclosing said impeller and having a generally cylindrical configuration and formed of a front section and a rear section; a multiplicity of bolts extending axially through said front and rear sections of said housing at spaced angular positions around the periphery thereof for holding said sections in an assembled condition, said rear section having a plurality of axiallyextending protuberances formed on the outer surface thereof; a mounting ring afiixed to said protuberances and surrounding the axis of rotation of said pump shaft; and means securing said mounting ring to said motor casing.

2. The combination defined in claim 1 in which one of said pump housing sections has an annular taper formed on the inner face thereof adjacent its periphery, and the other of said sections has an annular groove formed in the inner face thereof adjacent said taper, and an O-ring disposed in said groove and distorted into a sealing configuration by said taper.

3. A pump and drive motor combination for corrosive liquids including: a drive motor comprising a drive shaft with a counterbore therein and a casing; a pump shafts extending into said counterbore in axial alignment with said drive shaft and coupled thereto; a pump impeller mounted on the end of said pump shaft remote from said drive shaft; a pump housing enclosing said impeller having a generally cylindrical configuration and formed of a front section and a rear section; a multiplicity of bolts extending axially through said front and rear sections of said housing at spaced angular positions around the periphery thereof for holding said sections in an assembled condition; one of said pump housing sections having an annular taper formed in the inner face thereof adjacent its periphery and the other of said sections having an annular groove formed in the inner face thereof adjacent said taper, and an O-ring disposed in said groove and distorted into a sealing configuration with said taper; said rear section having a plurality of axially-extending protuber ances formed on the outer surface thereof, and a mounting ring secured to said protuberances surrounding and in coaxial relationship with said pump shaft; means securing said mounting ring to said motor casing; a stationary seal mounted in said pump housing and surrounding said pump shaft in coaxial relationship therewith; and a rotating seal supported on said pump shaft in said pump housing in sealing relationship with said stationary seal and coupled to said impeller.

4. The combination defined in claim 3 in which said rotating seal is rotatably mounted on said pump shaft, and which includes pin means extending axially from said rotating seal into said impeller to cause said rotating seal to rotate with said impeller.

References Cited by the Examiner UNITED STATES PATENTS 2,687,693 8/1954 Hudson 103-25 3,016,841 1/1962 Albertson et al 10387 3,033,121 5/1962 Girton 10387 3,115,840 12/1963 Feltus 103-108 X 3,155,045 11/1964 Lown et al 103-l14 X ROBERT M. WALKER, Primary Examiner. 

1. A PUMP AND DRIVE MOTOR COMBINATION FOR CORROSIVE LIQUIDS INCLUDING: A DRIVE MOTOR COMPRISING A DRIVE SHAFT AND A CASING; PUMP SHAFT COUPLED TO SAID DRIVE SHAFT; A PUMP IMPELLER MOUNTED ON SAID PUMP SHAFT; A PUMP HOUSING ENCLOSING SAID IMPELLER AND HAVING A GENERALLY CYLINDRICAL CONFIGURATION AND FORMED OF A FRONT SECTION AND A REAR SECTION; A MULTIPLICITY OF BOLTS EXTENDING AXIALLY THROUGH SAID FRONT AND REAR SECTIONS OF SAID HOUSING AT SPACED ANGULAR POSITIONS AROUND THE PERIPHERY THEREOF FOR HOLDING SAID SECTIONS IN AN ASSEMBLED CONDITION, SAID REAR SECTION HAVING A PLURALITY OF AXIALLYEXTENDING PROTUBERANCES FORMED ON THE OUTER SURFACE THEREOF; A MOUNTING RING AFFIXED TO SAID PROTUBERANCES AND SURROUNDING THE AXIS OF ROTATION OF SAID PUMP SHAFT; AND MEANS SECURING SAID MOUNTING RING TO SAID MOTOR CASING. 